This relates generally to imaging systems and, more particularly, to imaging systems that have imaging pixels.
Modern electronic devices such as cellular telephones, cameras, and computers often use digital image sensors. Image sensors (sometimes referred to as imagers) may be formed from a two-dimensional array of image sensing pixels. Each pixel includes a photosensitive layer that receives incident photons (light) and converts the photons into electrical charge. Image sensors are sometimes designed to provide images to electronic devices using a Joint Photographic Experts Group (JPEG) format.
Conventional image sensors are fabricated on a semiconductor substrate using complementary metal-oxide-semiconductor (CMOS) technology or charge-coupled device (CCD) technology. In CMOS image sensors, a rolling shutter or a global shutter may be used. In a global shutter, every pixel in the image sensor may simultaneously capture an image, whereas in a rolling shutter each row of pixels may sequentially capture an image. In CMOS image sensors with rolling shutters or global shutters, read-out is typically performed on a line-by-line basis. However, these integration and read-out schemes limit the flexibility of the image sensors.
It would therefore be desirable to provide improved image sensors.